1. Field of the Invention
The present invention relates generally to surgical instruments, and more particularly to apparatus and method for cleaning a surgically prepared working surface.
2. Description of the Related Art
In traditional orthopedic surgery, bone is prepared to receive a prosthetic implant by first cutting or sculpting the bone with a manual or powered tool such as a saw, drill, or broach. Next, the exposed bone is usually cleaned with a sterile saline solution for lavage and irrigation. Finally, suction is applied to remove debris. Often, surgical sponges are inserted into a cavity or against the bone surface to absorb excess fluids.
Joint replacements are commonly but not necessarily secured with the aid of “joint cement” or biocompatible adhesives. A typical such cement is a polymethyl methacrylate. The success of such adhesives is thought to depend in part on proper preparation of the bone bed.
U.S. Pat. No. 5,037,437 to Matsen III (1991) discloses a significant improvement in the art of preparing bone surface for cemented joint replacement surgery. Matsen identified some of the previously unrecognized shortcomings of traditional liquid flushing lavage for preparation of the cancellous portions of an exposed bone bed. Matsen's invention was based on the finding that dry flowing gas directed at and into the sculpted bony bed effectively prepares the bone for prosthetic implantation. When a bone cement is also used, the use of gas increases the likelihood of strong mechanical interdigitation of the bone cement with the bone. A number of such advantages to the gas lavage technique are identified in U.S. Pat. No. 5,037,437; the enumerated advantages need not be repeated here. Additional advantages may exist which have not been identified. Matsen also suggests that carbon dioxide is especially well suited for use as the dry gas for bone lavage, being demonstrated safe for use in the human body. As he notes, “the very high diffusion coefficient of carbon dioxide causes it to present a significantly lower risk of embolism as compared to the use of nitrogen or oxygen.” Moreover, carbon dioxide gas is commonly available in hospital operating rooms, finding use in laparascopic surgery, for example.
Since the publication of the Matsen patent, tools have become available for preparing bony surfaces by sterile, dry gas lavage, or lavage with sterile admixtures of gas and liquid. A carbon dioxide lavage system is available, for example, from Kinamed, Inc. in Camarillo, Calif. (marketed under the trade name “CarboJet”). The use of carbon dioxide is believed to be more effective than liquid debris removal because a compressed gas jet creates strong, fluctuating pressure gradients, displacing debris rapidly and thoroughly. This method is more effective at removing fluid and fluid-suspended debris from the interstices of cancellous bone.
Although surgical gas lavage nozzles are available, typical nozzles must be used in concert with surgical suction tools. Simultaneous manipulation and coordination of both gas supply and suction is difficult. Flow of the gas is not well controlled or confined to the bony surface. Both suction and gas jet must be constantly moved in a drying pattern to effectively clean and dry the bony surface. The difficulty of this technique in increased in surgical situations that permit only limited access or interfere with the surgeon's freedom of motion. As one example, in knee replacement surgery several planar bone cuts are commonly made in the femur and tibia It is desirable to prepare these surfaces to receive prosthetics.
Many surgeons are currently employing a “minimally invasive” surgical technique for knee replacement, which involves making only a very small incision at the front of the knee. The very small incision does not permit full freedom to access the cut bone surfaces from any arbitrary angle. In fact, a gap of less than 12 millimeters may be accessible between the prepared femur and tibia surfaces. In some cases, a gap as small as 8 millimeters may be present. Conventional gas jet instruments and suction instruments are not well suited to access the planar cuts in the knee without more exposure than that offered in minimally invasive surgical techniques.
A need persists for specially adapted lavage devices and methods which can better access bony surfaces, and which more efficiently and conveniently prepare the surfaces to receive cement or implants. Any time saved in the operating room is of great value (medically and economically) to both surgeon and patient.